Composite plastic container



, EJCCQNNLL COEPOSTE LSTIC CONTAINER @riginal Filed Aug. l` 3.957

3,l99,757 @@Mlil'll ilrAS'ilC CNTAlNEi?. Albert L. McConnell, Chester,Pa., assigner to Scott Paper Company, Philadelphia, in., a corporationoi Pennsylvania (ontinuation of application Ser. No. 675,629, Aug, l,1957. This application, Nov. 2i), i962, Ser. No. 2%,644 3 Claims. (Ci.22g- 1.5)

This application is a continuation of Serial No. 675,- 629, tiled Augusti, 1957, and now abandoned.

The present invention relates to containers and more particularly tocontainers formed ot organic'thermoplastics resins wherein is includedsupplementary insulating and reinforcing strata as an integralcomponent.

It is well recognized that the customary form of single service papercontainer possesses numerous material disadvantages which impede generalutilization thereof. The base stock of such containers is susceptible ofmechanical deterioration and even disintegration when exposed to waterbase-liquids. Additionally, the usual paper container has a glued seamor joint which can be the source of failure, particularly when thecontainer is employed in the handling of heated fluids. 'In order toobviate these use-limiting weaknesses, resin and wax coatings orimpregnation of the base stock has been employed although suchexpedients have necessarily restricted the fields of applicability ofthe specially processed containers. For example, coated or lled paperstock, of a strength adequate to resist mechanical deterioration, willfrequentlyl occasion contamination of the materials brought into contacttherewith. Manitestly, such material pollution is most undesirable.Furthermore, the increased cost of the specially processed containersreduces their commercial desirability and it is largely this cost factorwhich has precluded a more widespread adoption of resin impregnatedand/or surfaced containers.

Material costs have similarly limited consideration of syntheticplastics as stock from which single service containers could be formeddespite their increasing acceptance as substitutes for the morecustomary metallic, vitreous and ceramic substances entering commonappliance and dishware manufactures with improved production techniquesserving to enhance their desirability.

It is a principal object of the present invention to provide a strong,durable, lealrproof container formed of an organic thermoplasticresinous material which will be competitive costwise with the moreconventional paper containers, and which will be simple to manufacture.

. It is a further object of my invention to provide a single servicecontainer formed of an organic thermoplastic resinous material withwhich has been combined a lateral insulating stratum or thermal barrieradapting said container as a receptacle ot heated liquids.

Another object of my invention is to provide a single servicecontainervformed of a shaped organic thermoplastic resinous material with whichhas been combined a lateral reinforcing stratum to effect support ofside walls.

Other objects and advantages of my invention will be readily apparentfrom the following detailed description of certain preferred embodimentsthereof when taken in conjunction with the accompanying drawing,wherein:

FIGURE 1 is a view in elevation with parts broken away to show avertical section of a container constructed in accordance with theprovisions of my invention, and

FIGURE 2 is a similar view of another form of my invention.

Brielly stated, the present invention contemplates a unitary containerof shaped organic thermoplastic resinous material wherein peripheralside walls are combined with a supplementary stratum adequate for theirrein- Y ldhjii iatenteri Aug.' it?, i965 is it@ forcing support whileadditionally reducing thermal transmission therethrough.

Turning to the drawing, a container l, which may be of any desiredcross-sectional conguration although for convenience is depicted asbeing cup-shape, includes a peripheral side wall 2 and an integralbottom 3 of o1'- ganic thermoplastic resinous material. The side wall Zterminates in an upper rim 4 which provides a finished pouring lip forthe container and also cooperates with the usual type of closure orrictionally engaging lid normally employed therewith.

As shown in FIGURE l of the drawing, the wall 2 and bottom 3 of thecontainer include an exterior layer 5 composed of a cellulated organicthermoplastic material which may be of the sante composition as theother material in the container l or if desired may be selected from adierent thermoplastic resin. This layer 5 is integrated with the wall 2and bottom 3 of the container 'i during the initialformingthereof, thedrawing or molding operation serving to laminate and unite the separatelayers of thermoplastic resin entering the composite article.. The rsolid and cellulated layers of plastic may, of course, be united priorto the molding operation in order to minimize sheet displacement duringhandling, or if it is desired, the solid and cellulated layers ofplastic may be ,shaped separately into conforming liner and envelopelements which are subsequently assembled in the composite container.

In the forming operation, the individual cells within the body of thecellulated plastic material will be elongated and there is imparted tothe cellulated material and through it to the composite a rigiditygreatly in excess of that of the unstretched sheet or of the basematerial of the wall 2. ln addition, as is to be expectedrthe cellulatedmaterial will have a greatly reduced rate of thermal transmissiontherethrough, effectively insulating the composite container againstheat losses through its sidewall V and bottom.

As shown in FIGURE 2, the insulating and reinforcing cellulated layer Smay be disposed inwardlyof the Icontainer 1 and if it is desiredadditional reinforcing 7 such as a mat of woven glass fibers, a mesh ofsuitable fibrous' material or the like may be interposed between thelayers of thermoplastic resin prior to their lamination and molding. v

The several elements of the container i are shaped by standard plasticforming techniques, as for example, by vacuum assisted, plug molding ofheated sheets of organic thermoplastic resins in multiple molds. Themechanics of such molding operations are well known to those skilled inthe art and either uid or mechanical pressure or a combination of bothis equally satisfactory in obtaining the necessary plastic ow of theresinous material yto conform it to the particular mold configuration.These practices generally result in attenuation of the intermediateportion of the sbeeted plastic which enters into the side wall of themolded article and, While objectionable to many products, is in factbenecial in the present case. A lesser amount of plastic material willbe required in the formation of each container and accordingly thisreduction in wall thickness is deliberately sought by a controlled,diterential heating of the plastic affecting its flow characteristics,or by other means, such as regulation of the annular area to whichmaterial stretching may be substantially confined. Again the manner ofcontrollingv movement of the plastic material during the molding andforming operations, the edge clamping, localized heating,

plug sizes and the lil/re are well known and require no furtheramplification here.

Although a reduced weight of plastic material is involved in theformation ofthe container l making it more price competitive with thesci-called single service paper 3 container, the noted reinforcement ofthe composite side wall provides therefor the strength and rigiditynecessary for normall usage. Lateral compression forces exerted againstthe side wall 2 exteriorly thereof will not cause an undesirabledeformation or collapse of the container,

which will be fully self-supporting and form-retaining.

One important factor to be considered in the present invention is thatthe reduced costs incident thereto enables successful competition on aprice-per-unit basis with both paper and plastic containers ofcomparably size and use characteristics and provides a more satisfactoryproduct to the ultimate consumer.

Although the composite container of my invention `has a double thicknessof material in its body, the weight thereof is considerably less thanthat of the conventional double wound, hot-type, single service papercup. My composite plastic container is an 8-ounce practical capacitysize, will weigh approximately 7 grams, while the paper cup will weighalmost 50% more, that is, about 10 grams. The conventional injectionmolded plastic cup, which is devoid of the insulating characteristics ofmy composite container, in an equivalent size will weigh about 30% more,that is, about 9 grams.

Any of the conventional organic thermoplastic resinous materials may beemployed in the production of containers as contemplated by myinvention. The polystyrenes, including the nuclearly substituted alkylstyrenes, polyvinyl chlorides, polyvinylidene chlorides, polyalkylenessuch as polyethylene, polypropylene or polybutylene, methylmethacrylates. acrylates, vinyl acetate-vinyl chlon'de copolymersandadmixtures of different thermoplasticresins with themselves and withvarious fillers and extenders are readily moulded or drawn intocontainers of any desired cross-sectional configuration Aand dimensions.It is, of course, essential that the selected thermoplastic resin havegood flow characteristics during the molding or drawing operations inorder that dimensional controls will be possible. Manifestly, therefore,modification of the resinous materials to meet desired specificationsshould be possible. The incorporation therewith of A any of thecompatible plasticizers well known in the art, for example, dibutylphthalate, dioctyl sebacate, cyclohexyl naphthenate and others, iscontemplated. The resinous materials should also be susceptible ofcelluation or foaming through the inclusion therewith of gassing agents,vaporizable substances and the like and the techniques well known tothose skilled in the art permit any desired degree of cellulation aswell as control of cell size in order to meet specific characteristicsin the uitimate composite sheet.

It is preferred to employ a polystyrene resin having a softening pointof 180 F. or above as the basic plastic of my composite container and touse a polystyrene which has been cellulated and sheeted 4in accordancewith the method described in U.S. Patent No. 2,023,204, issued December3, 1935, to Munters et al. for the reinforcing and insulating layerwhich is integrated therewith. Matching-sheets of plain and cellulatedpolystyrene are processed together to produce containers of any desiredconfiguration and dimensions as established by the mold size and shape,the separate sheets being joined together into a composite unit duringthe molding or drawing operation.

' Example A polystyrene sheet having a thickness of 0.020" was heated toa temperature of about 200 F. and through conventional vacuum assistedplug molding, transformed into the conventional drinking cup offrusto-conical configuration. A cup of 8-ounce practical capacityweighed 4 grams and in the drawing operation, the thickness of theplastic in the side Wallof the cup was diminished to from 0.004" to0.010". Although the finished cup was self-supporting, the walls wereobjectionably flexible and compressible.

By combining a sheet of foamedv polystyrene having a thickness of 0.030with a sheetof unfoamed polystyrene of 0.020 thickness, and subjectingthe assembly to the same molding operation, a cup was formed in whichthe side wall had a thickness of from 0.0l5 to 0.0227 'while its weightin an 8-ounce size was 7-`grams.

The finished composite cup .was self-supporting and the walls were-onlyslightly exible. The culluated polystyrene layer reinforced and solidpolystyrene layer and the united wall structure possessed a rigiditygreatly in excess of that possible by mere increase in thickness of thesolid polystyrene layer to an equivalent extent.

The layer of cellulated resin included within the container bodyeonstitutesanv effective thermalzbarrier to enable comfortable handlingof the container when it is filled with hot liquids. Additionally, thereduced heat transmission factor of the cellulated resin enhances itsresistance to heat distortion and permits use of the composite containeras a receiver for liquids heated to a temperature which wouldundesirably deform a plastic container not .similarly protected. It hasalso been observed that both hot and cold liquids and foods willexperience less rapid changes in original temperature during theirretention in my composite container. v

It will be readily apparent that various modifications in the selectionof the elements entering the described container` construction,theircombination and arrangement are possible without departing from thespirit of the invention or the scope ofthe appended claims.

What I claim'is:

l. A thermoplastic article of manufacture suitable for directlyreceiving contents usable for human consumption, the said containercomprising a unitary circular side wall, a bottom seamlessly fullyintegrated with said side wall, and a circumferential lip, the saidcontainer characterized as having a side wall Ain a truste-conicalshape, tapering downwardly from a larger diameter adjacent -to its upperend, seamlessly, fully integrated with said lip,the said side walltapering to a smaller diameter and seamlessly, fully integrated withsaid bottomvend, the said side wall, bottom and lip being substantiallyfree from defects caused by wrinkles, folds and breaks in its structure,the said container having an outer shell of a polystyrene foam organicmaterial, and an interior liner of a hard, smooth, seuiresistant,enamel-like polystyrene solid material, said outer shell and liner beingintegrally united without interposition of an adhesive, the saidcircumferential lip being nished exposing the hard, enamellike interiorliner in a circumferential partial annulus at the said receiving openingof said frusto-conical container, the said side Wall characterized byhaving one layer of said foam material, and one layer of an interiormaterial of a unitary, seamless structure having the said outer foammaterial and the said interior material thermally, compositely united,the unitary side wall construction being self-supporting andsubstantially expandingly, non-bulging when said container `is in aloaded condition, said side wall being paperlike and of a thickness offrom about 0.015" to about 0.022, the said side wall being furthercharacterized 4by the partial compressive flexibility and recovery oforiginal shape without breaking and destroying vthe impermeability ofsaid hard enamel-like interior liner, without breaking and permanentlycreasing the outer foam layer and without destroying. the bond betweenthe contiguous, thermally compositely united foam layer and said inte'or liner, the said side wall having a relatively rough surface incomparison with the interior due to the attenuated foam structure, thesaid foam structure imparting complementary rigidity to said moreflexible interior liner, the said bottom characterized by being lessflexible thanlsaid side wall, thereby imparting structural, dimensionalstability to said flexible side wall, the said seamlessly, fullyincorporatedA circumferential lip characterized by being less flexiblethan said side wall but more flexible than said bottom, the said lipthereby imparting dimensional stability by resisting breakin-y. thc saidcontainer lacing .fudher chaructcrized by the seamless diflcrcntialrigidity of said seamless bottom, seamless lip and seamless side wall,the

differential rigidity in` the unitary, continuons,:se`:,imless containerco-'acting to impart structural, dimensional stability-to saidcontainer, the dimensional stability being 2.' The thermohlastic articleof manufacture of claim I wherein the total weight of an approximately8o`unce by volume containeris about 7 grams, and said truste-conicalshape defining a stackable cup article.

. 3. A thin-walled, thermoplastic, compositely united con'v tainercomprised of a unitary, seamless structure of a side wall, a bottomseamlessly fully integral with said side wall, and a smoothly finishedupper rim seamlessly fully integral with said side wall, said containerhaving anexterior of at least one layer of an attenuated foam sheet ofplastic .characterized by a high volume ratio per total weight ofvcontainer.

material and an interior liner sheet of a hard, smooth, 4

'scudi-resistant, enamel-like plastic material, the said exterior andinterior sheets being unitarily setfwithou't an interposed adhesive andbeing of a unitary, seamless,

thermal-set construction, the said bottom beingfurtherch'a'ract-erized'by` being less' flexible Athan said side wall,-

'thereby imparting structural, dimensional stability to saidfl'cl'iblc;` sidewall, the said rim characterized. byibeing moreexiblc'lthan saidfbc'ittom, butless flexible 'than-said sidewalltoltrpparfegmgpsianal stability to saidside wau'to resistlbicakin'gQtHe Unia'f'ylside walleonstruction mmt- Vpartial compressiveflexibility. and recovery oforiginal- Shape without breaking anddestroying the impermeability o f said hard 'ehamel-Qlike .interiorliner, without breaking and permanently creasing the outer foain layer,`andwithcui vdestroying'v the thermally bonded, unitary,A composite offoam sheet andinterirliner.

Rferenes cited bythe Examiner UNITED' s TArEsjPATENTs 2,150,910'V 3/39Chaplin' 229-25.l 2,722,719 u /ss-Anstadren V 'i- 2,737,503 3/ 56Sprague V. 26o-25 .2,834,533 -3/5 s Carelw 22a- 1.5 2,917,217 12/59sisson Y A ,2293.5

2,942,301 6/.60 YPrim: etal. 3,037,652 6/62 Wallace.

afhaal mme Futiigg'jfmotiemrissucs, gember-i950.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION atent Nor,3,199,75P7 August l0, 1965 Albert Lo McConnell It is hereby certifiedthat error appears n the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 3, line 10, for "comparably" read Comparable M; column 4, line 8,for "culluated" read f Qellulated n; Column 6, line 4, for "the" read beH Signed and sealed thls 28th day of June 196@ (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

1. A THERMOPLASTIC ARTICLE OF MANUFACTURE SUITABLE FOR DIRECTLYRECEIVING CONTENNTS USABLE FOR HUMAN CONSUMPTION, THE SAID CONTAINERCOMPRISING A UNITARY CIRCULAR SIDE WALL, A BOTTOM SEAMLESSLY FULLYINTEGRATED WITH SAID SIDE WALL, AND A CIRCUMFERENTIAL LIP, THE SAIDCONTAINER CHARACTERIZED AS HAVING A SIDE WALL IN A FRUSTO-CONICAL SHAPE,TAPERING DOWNWARDLY FROM A LARGER DIAMETER ADJACENT TO ITS UPPER END,SEAMLESSLY, FULLY INTEGRATED WITH SAID LIP, THE SAID SIDE WALL TAPERINGTO A SMALLER DIAMETER AND SEAMLESSLY, FULLY INTEGRATED WITH SAID BOTTOMEND, THE SAID SIDE WALL, BOTTOM AND LIP BEING SUBSTANTIALLY FREE FROMDEFECTS CAUSED BY WRINKLES, FOLDS AND BREAKS IN ITS STRUCTURE, THE SAIDCONTAINER HAVING AN OUTER SHELL OF A POLYSTYRENE FOAM ORGANIC MATERIAL,AND AN INTERIOR LINER OF A HARD, SMOOTH, SCUFFRESISTANT, ENAMEL-LIKEPOLYSTYRENNE SOLID MATERIAL, SAID OUTER SHELL AND LINER BEING INTEGRALLYUNITED WITHOUT INTERPOSITION OF AN ADHESIVE, THE SAID CIRCUMFERENTIALLIP BEING FINISHED EXPOSING THE HARD, ENAMEL-LIKE INTERIOR LINER IN ACIRCUMFERENTIAL PARTIAL ANNULUS AT THE SAID RECEIVING OPENING OF SAIDFRUSTO-CONICAL CONTAINER, THE SAID SIDE WALL CHARACTERIZED BY HAVING ONELAYER OF SAID FOAM MATERIAL, AND ONE LAYER OF AN INTERIOR MATERIAL OF AUNITARY, SEAMLESS STRUCTURE HAVING THE SAID OUTER FOAM MATERIAL AND THESAID INTERIOR MATERIAL THERMALLY, COMPOSITELY UNITED, THE UNITARY SIDEWALL CONSTRUCTION BEING SELF-SUPPORTING AND SUBSTANTIALLY EXPANDINGLY,NON-BULGING WHEN SAID CONTAINER IS IN A LOADED CONDITION, SAID SIDE WALLBEING PAPERLIKE AND OF A THICKNESS OF FROM ABOUT 0.015" TO ABOUT 0.022",THE SAID SIDE WALL BEING FURTHER CHARACTERIZED BY THE PARTIALCOMPRESSIVE FLEXIBILITY AND RECOVERY OF ORIGINAL SHAPE WITHOUT BREAKINGAND DESTROYING THE IMPERMEABILITY